1. Field of the Invention
This invention relates to a wear-detection probe for a brake lining material in a vehicle such as a motorcar.
2. Statement of the Prior Art
A brake for a vehicle generates a braking force by pressing a lining material, such as a shoe lining in a drum brake or a brake pad in a disc brake, on a rotor. It is possible to improve the safety of the brake by detecting the amount of wear of the lining material and generating a warning signal before the lining material has been overworn.
As means for detecting the usable limit of brake lining material with respect to wear, there is a known contact type or disconnection type wear-detection device which has a probe provided in or near the brake lining material with a conductor which is either contacted with the rotor or cut off by the rotor when the brake lining material is worn by a predetermined amount, and which turns on a warning light to indicate the wear of the lining material when the conductor is either contacted with the rotor or cut off by the rotor.
For convenience of explanation, a conventional wear-detection probe for brake lining material will be described below by referring to FIGS. 16 and 17.
FIG. 16 shows a probe 100 in a disconnection type wear-detection device, which comprises a detection part 101 having a loop-like circuit conductor B connected to a controller A and a housing 102 made of a resin material for receiving the detection part 101. The probe 100 is secured to a back metal D of the brake lining material C with the detection part 101 being inserted into the brake lining material C. In the probe 100 shown in FIG. 16, the detection part 101 is cut off by a rotor (not shown), when the brake lining material C is worn by a given amount.
FIG. 17 shows a probe 200 in a contact type wear-detection device. The probe 200 comprises a detection part 201 on an end of a circuit conductor B' connected to a controller A' and a housing 202 supporting the detection part 201. The probe 200 shown in FIG. 17 is secured to the back metal D of the brake lining material C with the detection part being inserted into the material C. In the probe 200 in FIG. 17, the detection part 201 contacts with the rotor R which rotates by wheels and then conducts the electric current in the controllers when the brake lining material C is worn by a given amount.
The above wear-detection of the brake lining material in the disconnection type or contact type wear-detection device is accompanied by breakage of the probe. Accordingly, it is necessary to exchange an old probe for a new one once the probe has detected the wear of the brake lining material.
However, since the detection parts 101 and 201 in the conventional probes shown in FIGS. 16 and 17 are formed together with the circuit conductors B and B', it is necessary to change the circuit conductors B and B' which connect the probes 100 and 200 to the controllers A and A' in the wear-detection device, as well as the probes 100 and 200 once the wear-detection is completed. That is, since the harness must be changed in the conventional probe whenever the wear-detection has been completed, the costs of the parts to be prepared and changing them are increased.